summaryrefslogtreecommitdiff
path: root/Documentation/git-rebase.txt
blob: 26f3b7b2b0daad0affb36e6514156520a693b164 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
git-rebase(1)
=============
 
NAME
----
git-rebase - Forward-port local commits to the updated upstream head
 
SYNOPSIS
--------
[verse]
'git rebase' [-i | --interactive] [options] [--onto <newbase>]
	<upstream> [<branch>]
'git rebase' [-i | --interactive] [options] --onto <newbase>
	--root [<branch>]
 
'git rebase' --continue | --skip | --abort
 
DESCRIPTION
-----------
If <branch> is specified, 'git-rebase' will perform an automatic
`git checkout <branch>` before doing anything else.  Otherwise
it remains on the current branch.
 
All changes made by commits in the current branch but that are not
in <upstream> are saved to a temporary area.  This is the same set
of commits that would be shown by `git log <upstream>..HEAD` (or
`git log HEAD`, if --root is specified).
 
The current branch is reset to <upstream>, or <newbase> if the
--onto option was supplied.  This has the exact same effect as
`git reset --hard <upstream>` (or <newbase>).  ORIG_HEAD is set
to point at the tip of the branch before the reset.
 
The commits that were previously saved into the temporary area are
then reapplied to the current branch, one by one, in order. Note that
any commits in HEAD which introduce the same textual changes as a commit
in HEAD..<upstream> are omitted (i.e., a patch already accepted upstream
with a different commit message or timestamp will be skipped).
 
It is possible that a merge failure will prevent this process from being
completely automatic.  You will have to resolve any such merge failure
and run `git rebase --continue`.  Another option is to bypass the commit
that caused the merge failure with `git rebase --skip`.  To restore the
original <branch> and remove the .git/rebase-apply working files, use the
command `git rebase --abort` instead.
 
Assume the following history exists and the current branch is "topic":
 
------------
          A---B---C topic
         /
    D---E---F---G master
------------
 
From this point, the result of either of the following commands:
 
 
    git rebase master
    git rebase master topic
 
would be:
 
------------
                  A'--B'--C' topic
                 /
    D---E---F---G master
------------
 
The latter form is just a short-hand of `git checkout topic`
followed by `git rebase master`.
 
If the upstream branch already contains a change you have made (e.g.,
because you mailed a patch which was applied upstream), then that commit
will be skipped. For example, running `git rebase master` on the
following history (in which A' and A introduce the same set of changes,
but have different committer information):
 
------------
          A---B---C topic
         /
    D---E---A'---F master
------------
 
will result in:
 
------------
                   B'---C' topic
                  /
    D---E---A'---F master
------------
 
Here is how you would transplant a topic branch based on one
branch to another, to pretend that you forked the topic branch
from the latter branch, using `rebase --onto`.
 
First let's assume your 'topic' is based on branch 'next'.
For example, a feature developed in 'topic' depends on some
functionality which is found in 'next'.
 
------------
    o---o---o---o---o  master
         \
          o---o---o---o---o  next
                           \
                            o---o---o  topic
------------
 
We want to make 'topic' forked from branch 'master'; for example,
because the functionality on which 'topic' depends was merged into the
more stable 'master' branch. We want our tree to look like this:
 
------------
    o---o---o---o---o  master
        |            \
        |             o'--o'--o'  topic
         \
          o---o---o---o---o  next
------------
 
We can get this using the following command:
 
    git rebase --onto master next topic
 
 
Another example of --onto option is to rebase part of a
branch.  If we have the following situation:
 
------------
                            H---I---J topicB
                           /
                  E---F---G  topicA
                 /
    A---B---C---D  master
------------
 
then the command
 
    git rebase --onto master topicA topicB
 
would result in:
 
------------
                 H'--I'--J'  topicB
                /
                | E---F---G  topicA
                |/
    A---B---C---D  master
------------
 
This is useful when topicB does not depend on topicA.
 
A range of commits could also be removed with rebase.  If we have
the following situation:
 
------------
    E---F---G---H---I---J  topicA
------------
 
then the command
 
    git rebase --onto topicA~5 topicA~3 topicA
 
would result in the removal of commits F and G:
 
------------
    E---H'---I'---J'  topicA
------------
 
This is useful if F and G were flawed in some way, or should not be
part of topicA.  Note that the argument to --onto and the <upstream>
parameter can be any valid commit-ish.
 
In case of conflict, 'git-rebase' will stop at the first problematic commit
and leave conflict markers in the tree.  You can use 'git-diff' to locate
the markers (<<<<<<) and make edits to resolve the conflict.  For each
file you edit, you need to tell git that the conflict has been resolved,
typically this would be done with
 
 
    git add <filename>
 
 
After resolving the conflict manually and updating the index with the
desired resolution, you can continue the rebasing process with
 
 
    git rebase --continue
 
 
Alternatively, you can undo the 'git-rebase' with
 
 
    git rebase --abort
 
CONFIGURATION
-------------
 
rebase.stat::
	Whether to show a diffstat of what changed upstream since the last
	rebase. False by default.
 
OPTIONS
-------
<newbase>::
	Starting point at which to create the new commits. If the
	--onto option is not specified, the starting point is
	<upstream>.  May be any valid commit, and not just an
	existing branch name.
 
<upstream>::
	Upstream branch to compare against.  May be any valid commit,
	not just an existing branch name.
 
<branch>::
	Working branch; defaults to HEAD.
 
--continue::
	Restart the rebasing process after having resolved a merge conflict.
 
--abort::
	Restore the original branch and abort the rebase operation.
 
--skip::
	Restart the rebasing process by skipping the current patch.
 
-m::
--merge::
	Use merging strategies to rebase.  When the recursive (default) merge
	strategy is used, this allows rebase to be aware of renames on the
	upstream side.
 
-s <strategy>::
--strategy=<strategy>::
	Use the given merge strategy.
	If there is no `-s` option, a built-in list of strategies
	is used instead ('git-merge-recursive' when merging a single
	head, 'git-merge-octopus' otherwise).  This implies --merge.
 
-v::
--verbose::
	Be verbose. Implies --stat.
 
--stat::
	Show a diffstat of what changed upstream since the last rebase. The
	diffstat is also controlled by the configuration option rebase.stat.
 
-n::
--no-stat::
	Do not show a diffstat as part of the rebase process.
 
--no-verify::
	This option bypasses the pre-rebase hook.  See also linkgit:githooks[5].
 
-C<n>::
	Ensure at least <n> lines of surrounding context match before
	and after each change.  When fewer lines of surrounding
	context exist they all must match.  By default no context is
	ever ignored.
 
-f::
--force-rebase::
	Force the rebase even if the current branch is a descendant
	of the commit you are rebasing onto.  Normally the command will
	exit with the message "Current branch is up to date" in such a
	situation.
 
--whitespace=<option>::
	This flag is passed to the 'git-apply' program
	(see linkgit:git-apply[1]) that applies the patch.
	Incompatible with the --interactive option.
 
--committer-date-is-author-date::
--ignore-date::
	These flags are passed to 'git-am' to easily change the dates
	of the rebased commits (see linkgit:git-am[1]).
 
-i::
--interactive::
	Make a list of the commits which are about to be rebased.  Let the
	user edit that list before rebasing.  This mode can also be used to
	split commits (see SPLITTING COMMITS below).
 
-p::
--preserve-merges::
	Instead of ignoring merges, try to recreate them.
 
--root::
	Rebase all commits reachable from <branch>, instead of
	limiting them with an <upstream>.  This allows you to rebase
	the root commit(s) on a branch.  Must be used with --onto, and
	will skip changes already contained in <newbase> (instead of
	<upstream>).  When used together with --preserve-merges, 'all'
	root commits will be rewritten to have <newbase> as parent
	instead.
 
include::merge-strategies.txt[]
 
NOTES
-----
 
You should understand the implications of using 'git-rebase' on a
repository that you share.  See also RECOVERING FROM UPSTREAM REBASE
below.
 
When the git-rebase command is run, it will first execute a "pre-rebase"
hook if one exists.  You can use this hook to do sanity checks and
reject the rebase if it isn't appropriate.  Please see the template
pre-rebase hook script for an example.
 
Upon completion, <branch> will be the current branch.
 
INTERACTIVE MODE
----------------
 
Rebasing interactively means that you have a chance to edit the commits
which are rebased.  You can reorder the commits, and you can
remove them (weeding out bad or otherwise unwanted patches).
 
The interactive mode is meant for this type of workflow:
 
1. have a wonderful idea
2. hack on the code
3. prepare a series for submission
4. submit
 
where point 2. consists of several instances of
 
a. regular use
 1. finish something worthy of a commit
 2. commit
b. independent fixup
 1. realize that something does not work
 2. fix that
 3. commit it
 
Sometimes the thing fixed in b.2. cannot be amended to the not-quite
perfect commit it fixes, because that commit is buried deeply in a
patch series.  That is exactly what interactive rebase is for: use it
after plenty of "a"s and "b"s, by rearranging and editing
commits, and squashing multiple commits into one.
 
Start it with the last commit you want to retain as-is:
 
	git rebase -i <after-this-commit>
 
An editor will be fired up with all the commits in your current branch
(ignoring merge commits), which come after the given commit.  You can
reorder the commits in this list to your heart's content, and you can
remove them.  The list looks more or less like this:
 
-------------------------------------------
pick deadbee The oneline of this commit
pick fa1afe1 The oneline of the next commit
...
-------------------------------------------
 
The oneline descriptions are purely for your pleasure; 'git-rebase' will
not look at them but at the commit names ("deadbee" and "fa1afe1" in this
example), so do not delete or edit the names.
 
By replacing the command "pick" with the command "edit", you can tell
'git-rebase' to stop after applying that commit, so that you can edit
the files and/or the commit message, amend the commit, and continue
rebasing.
 
If you want to fold two or more commits into one, replace the command
"pick" with "squash" for the second and subsequent commit.  If the
commits had different authors, it will attribute the squashed commit to
the author of the first commit.
 
In both cases, or when a "pick" does not succeed (because of merge
errors), the loop will stop to let you fix things, and you can continue
the loop with `git rebase --continue`.
 
For example, if you want to reorder the last 5 commits, such that what
was HEAD~4 becomes the new HEAD. To achieve that, you would call
'git-rebase' like this:
 
----------------------
$ git rebase -i HEAD~5
----------------------
 
And move the first patch to the end of the list.
 
You might want to preserve merges, if you have a history like this:
 
------------------
           X
            \
         A---M---B
        /
---o---O---P---Q
------------------
 
Suppose you want to rebase the side branch starting at "A" to "Q". Make
sure that the current HEAD is "B", and call
 
-----------------------------
$ git rebase -i -p --onto Q O
-----------------------------
 
 
SPLITTING COMMITS
-----------------
 
In interactive mode, you can mark commits with the action "edit".  However,
this does not necessarily mean that 'git-rebase' expects the result of this
edit to be exactly one commit.  Indeed, you can undo the commit, or you can
add other commits.  This can be used to split a commit into two:
 
- Start an interactive rebase with `git rebase -i <commit>^`, where
  <commit> is the commit you want to split.  In fact, any commit range
  will do, as long as it contains that commit.
 
- Mark the commit you want to split with the action "edit".
 
- When it comes to editing that commit, execute `git reset HEAD^`.  The
  effect is that the HEAD is rewound by one, and the index follows suit.
  However, the working tree stays the same.
 
- Now add the changes to the index that you want to have in the first
  commit.  You can use `git add` (possibly interactively) or
  'git-gui' (or both) to do that.
 
- Commit the now-current index with whatever commit message is appropriate
  now.
 
- Repeat the last two steps until your working tree is clean.
 
- Continue the rebase with `git rebase --continue`.
 
If you are not absolutely sure that the intermediate revisions are
consistent (they compile, pass the testsuite, etc.) you should use
'git-stash' to stash away the not-yet-committed changes
after each commit, test, and amend the commit if fixes are necessary.
 
 
RECOVERING FROM UPSTREAM REBASE
-------------------------------
 
Rebasing (or any other form of rewriting) a branch that others have
based work on is a bad idea: anyone downstream of it is forced to
manually fix their history.  This section explains how to do the fix
from the downstream's point of view.  The real fix, however, would be
to avoid rebasing the upstream in the first place.
 
To illustrate, suppose you are in a situation where someone develops a
'subsystem' branch, and you are working on a 'topic' that is dependent
on this 'subsystem'.  You might end up with a history like the
following:
 
------------
    o---o---o---o---o---o---o---o---o  master
	 \
	  o---o---o---o---o  subsystem
			   \
			    *---*---*  topic
------------
 
If 'subsystem' is rebased against 'master', the following happens:
 
------------
    o---o---o---o---o---o---o---o  master
	 \			 \
	  o---o---o---o---o	  o'--o'--o'--o'--o'  subsystem
			   \
			    *---*---*  topic
------------
 
If you now continue development as usual, and eventually merge 'topic'
to 'subsystem', the commits from 'subsystem' will remain duplicated forever:
 
------------
    o---o---o---o---o---o---o---o  master
	 \			 \
	  o---o---o---o---o	  o'--o'--o'--o'--o'--M	 subsystem
			   \			     /
			    *---*---*-..........-*--*  topic
------------
 
Such duplicates are generally frowned upon because they clutter up
history, making it harder to follow.  To clean things up, you need to
transplant the commits on 'topic' to the new 'subsystem' tip, i.e.,
rebase 'topic'.  This becomes a ripple effect: anyone downstream from
'topic' is forced to rebase too, and so on!
 
There are two kinds of fixes, discussed in the following subsections:
 
Easy case: The changes are literally the same.::
 
	This happens if the 'subsystem' rebase was a simple rebase and
	had no conflicts.
 
Hard case: The changes are not the same.::
 
	This happens if the 'subsystem' rebase had conflicts, or used
	`\--interactive` to omit, edit, or squash commits; or if the
	upstream used one of `commit \--amend`, `reset`, or
	`filter-branch`.
 
 
The easy case
~~~~~~~~~~~~~
 
Only works if the changes (patch IDs based on the diff contents) on
'subsystem' are literally the same before and after the rebase
'subsystem' did.
 
In that case, the fix is easy because 'git-rebase' knows to skip
changes that are already present in the new upstream.  So if you say
(assuming you're on 'topic')
------------
    $ git rebase subsystem
------------
you will end up with the fixed history
------------
    o---o---o---o---o---o---o---o  master
				 \
				  o'--o'--o'--o'--o'  subsystem
						   \
						    *---*---*  topic
------------
 
 
The hard case
~~~~~~~~~~~~~
 
Things get more complicated if the 'subsystem' changes do not exactly
correspond to the ones before the rebase.
 
NOTE: While an "easy case recovery" sometimes appears to be successful
      even in the hard case, it may have unintended consequences.  For
      example, a commit that was removed via `git rebase
      \--interactive` will be **resurrected**!
 
The idea is to manually tell 'git-rebase' "where the old 'subsystem'
ended and your 'topic' began", that is, what the old merge-base
between them was.  You will have to find a way to name the last commit
of the old 'subsystem', for example:
 
* With the 'subsystem' reflog: after 'git-fetch', the old tip of
  'subsystem' is at `subsystem@\{1}`.  Subsequent fetches will
  increase the number.  (See linkgit:git-reflog[1].)
 
* Relative to the tip of 'topic': knowing that your 'topic' has three
  commits, the old tip of 'subsystem' must be `topic~3`.
 
You can then transplant the old `subsystem..topic` to the new tip by
saying (for the reflog case, and assuming you are on 'topic' already):
------------
    $ git rebase --onto subsystem subsystem@{1}
------------
 
The ripple effect of a "hard case" recovery is especially bad:
'everyone' downstream from 'topic' will now have to perform a "hard
case" recovery too!
 
 
Authors
------
Written by Junio C Hamano <gitster@pobox.com> and
Johannes E. Schindelin <johannes.schindelin@gmx.de>
 
Documentation
--------------
Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
 
GIT
---
Part of the linkgit:git[1] suite